52 



3. Sectile — may be cut into thin slices. 



4. Flexible — retains its form when bent. 



5. Elastic — comes back in its original form when bent. 

 V. Lustre. 



1. Metallic, as in metals. 



2. Non-metallic — vitreous, as in glass. Pearly, as in 

 pearl. Eesinous, as in sulphur, sphalerite, resins. Pitchy, 

 as in cannel coal. Silky or satiny, as in satin spar. 

 G-reasy, or waxy, as in serpentine. Dull, as in chalk. 



VI. Streak. — Color obtained by rubbing mineral over 

 surface of a piece of ground glass or file. 

 ^^11. Diaphaneity. 



1. Transparent, semi-transparent. 



2. Translucent, sub-translucent. 



3. Opaque. 



Vin. Acid tests. Use H. CI. (hydrochloric acid) or dilute 

 H^SO* (sulphuric acid), or both. Use a little of the 

 mineral in a test tube. 



1. Insoluble. 



2. Soluble. With effervescence, with or without heat. 

 Without effervescence, with or without heat. 



IX. Flame Tests. Use a fine splinter of the mineral, or 

 thin edge in the flame of an alcohol lamp or bunsen 

 burner. Note color imparted to flame. 



1. Fusible — melts. 



2. Infusible — does not melt. 



3. Decrepitates. Breaks into small pieces with crack- 

 ling sound. 



4. Intumesces.. Swells up without fusion. 

 Taken from "Nature Study," by W. S. Jackman. 



